<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <!-- v-on: 可替换@ -->
        <button v-on:mouseenter="count--">-</button>
        <span>{{ count }}</span>
        <button @mouseenter="count++">+</button>
        <button @click="fn">切换显示隐藏</button>
        <h1 v-show="isShow">Vue</h1>
    </div>
 
    <script src="https://cdn.jsdelivr.net/npm/vue@2.7.16/dist/vue.js"></script>

    <script>
        const app =  new Vue({
            el:"#app",
            data:{
                count:100,
                isShow:true
            },
            methods:{ 
                fn(){
                    // app.isShow=!app.isShow;
                    // console.log(app.isShow);
                    // console.log(this.isShow===app.isShow);
                    this.isShow=!this.isShow;
                }
            }
        })
    </script>
</body>
</html>